The cross-country diffusion of technology is a central driver of productivity growth and economic convergence. This paper provides novel evidence on the role of out-migration as a channel of technology transfer from destination to origin countries. We construct an individual-level dataset linking four million British immigrants in the US to the UK census (1870-1930) and digitize the universe of British patents granted in the nineteenth century. Using a shift-share design that leverages shocks to US innovation, together with text analysis of patents, we document that migration ties facilitated the diffusion of US technology to the UK. Return migration was an important driver of this effect. However, migrants' social networks at home fostered technology transfer even in the absence of physical return.

Between 1920 and 1921, Italian emigration to the United States dropped by 85% after the Emergency Quota Act, a severely restrictive immigration law, was passed by the US Congress. Using newly digitized data from Italian historical censuses in a difference-in-differences setting, we leverage variation in exposure across Italian districts to this large restriction on human mobility. More exposed districts display a sizable population increase. Moreover, the policy substantially hampered the adoption of labor-saving technology. Consistent with directed technology adoption theory, manufacturing employment increased markedly, and evidence suggests that "missing migrants," whose migration was inhibited by the Act, drive this result.

How do societies respond to adversity? We provide novel evidence focusing on the reaction to the 1918-1919 influenza pandemic in the United States. We document that counties hit harder by the pandemic became both more religious and more scientific. We investigate the underlying mechanism, examining how individuals within counties reacted to the shock. We uncover heterogeneous responses, with religion and science acting as substitute ways of coping with the pandemic. Facing adversity widened the distance in religiosity between science-oriented individuals and the rest of the population and increased the polarization of religious beliefs.

I examine how the Progressive-era Settlement movement impacted immigrant assimilation in the US between 1880 and 1940. Settlements provided job training, childcare, and language classes to immigrants in urban areas. Using an individual-level triple difference that leverages across-neighborhood, cross-cohort, and over-time variation in settlement exposure, I find that settlements had positive labor-market effects for men but not for women and increased segregation. These responses persisted into the generation exposed to settlements during childhood. The heterogeneous effects of settlements partly stemmed from increased fertility that excluded women from labor markets, particularly among immigrants from countries with more conservative gender norms.

Can racial discrimination harm innovation? We study this question using data on US inventors linked to population censuses in 1895-1925. Our novel identification strategy leverages plausibly exogenous variation in the timing of lynchings and the name of the victims. We find an immediate and persistent decrease in patents granted to inventors who share their names with the victims of lynchings, but only when victims are Black. We hypothesize that lynchings accentuate the racial content of the victim's name to patent examiners, who cannot observe the inventors' race from patent applications. We interpret these findings as evidence of discrimination by patent examiners and provide results against alternative mechanisms.

Patent protection is the most prevalent form of intellectual property protection, yet its impact on innovation and economic growth remains unclear. I introduce a difference-in-differences strategy exploiting the appointment of patent examiners at the U.S. Patent Office from 1919 to 1938. Newly appointed examiners grant 14% more patents to inventors from their home regions. Using examiners' appointments to isolate exogenous spatial variation in patent protection over time, I find that increased patenting fosters growth in manufacturing and income per capita. Increased patenting generates knowledge spillovers, which amplify subsequent innovation, in sectors technologically related to those of the newly appointed examiners.

This paper examines whether, in response to natural disasters, industrial policy can shape innovation toward risk-mitigating technologies. We study the 1871 Chicago Fire and the consequent policy banning wooden construction. Using a synthetic control framework, we find that construction patenting and manufacturing in Chicago increased sharply, with positive spillovers into related sectors. To distinguish the effects of the Fire and the policy, we compare wood and non-wood construction, showing that gains were concentrated in non-wood construction. Additionally, we study the 1872 Boston Fire, where no regulations were implemented, and find no effect on patenting and a modest rise in manufacturing.